Seasonal Affective Disorder (SAD) is a specific type of depression that occurs with the changing seasons, typically starting in late fall or early winter and remitting during the spring and summer months. This mood change is strongly correlated with a reduction in natural daylight hours. Many people wonder if the light exposure provided by indoor tanning beds could offer a therapeutic benefit similar to medically approved treatments.
Understanding Seasonal Affective Disorder
The primary mechanism of Seasonal Affective Disorder involves the way the brain responds to the decrease in environmental light during winter. Reduced natural light exposure can disrupt the body’s internal 24-hour clock, known as the circadian rhythm. This disruption often results in a phase-delay, causing the body’s internal timing to be out of sync with the external light-dark cycle.
The shift in the light cycle directly affects the balance of two neurochemicals: serotonin and melatonin. Serotonin, linked to mood regulation, decreases in production during the darker winter months. Conversely, melatonin, which regulates sleep, is produced for a longer duration when nights are longer, contributing to increased sleepiness and lethargy. These biochemical changes, driven by the lack of bright natural light, underlie the depressive symptoms experienced by individuals with SAD.
Medical Standard: Therapeutic Light Boxes
The medically accepted treatment for Seasonal Affective Disorder is light therapy, administered via light boxes. These devices mimic the effects of bright outdoor light without the dangers of ultraviolet radiation. The required intensity for effective treatment is 10,000 lux, which is significantly brighter than standard indoor lighting.
These light boxes utilize visible light to signal the brain and help reset the circadian rhythm. The light must be administered for a specific duration, typically 20 to 30 minutes each morning, to achieve a therapeutic effect. Crucially, established light therapy devices incorporate a filter to block nearly all ultraviolet (UV) light, ensuring the treatment is safe for the eyes and skin.
Tanning Beds and the SAD Question
Tanning beds emit light, but the spectrum differs from the visible light required for SAD treatment. Tanning devices produce ultraviolet (UV) radiation, primarily UVA and some UVB light, which stimulates melanin production for tanning purposes. This UV radiation is not the high-intensity visible light necessary to influence the brain’s circadian clock or neurotransmitter balance.
The therapeutic effect of light therapy relies on visible light entering the eye to reach specific receptors. Because tanning beds prioritize UV output over high-intensity visible light, they lack the necessary spectrum and lux intensity to be an effective intervention for SAD. They cannot serve as a substitute for a clinical light box.
Health Risks of Ultraviolet Exposure
The use of tanning beds carries health risks that far outweigh any minor psychological effect. The ultraviolet light emitted by these devices is classified as a human carcinogen by the World Health Organization. Exposure substantially increases the risk of developing melanoma, the deadliest form of skin cancer, as well as non-melanoma skin cancers like basal and squamous cell carcinomas.
Many commercial tanning beds emit UV radiation that can be several times more intense than the midday summer sun. Beyond cancer risk, this intense exposure accelerates the breakdown of collagen and elastin, leading to premature skin aging, wrinkles, and sunspots. UV radiation poses a serious threat to ocular health, causing photokeratitis, cataracts, and ocular melanoma.